1. Field of the Invention
The present invention relates to a sample observation apparatus, and in particular, relates to a sample observation apparatus that generates a sample image in which a super-resolution component is visualized.
2. Description of the Related Art
In scanning microscopes, light that is condensed to one spot on a sample is moved by a scanning unit such as a galvano mirror to scan the sample, and thereby the sample is observed. Such scanning microscopes are widely used in several technical fields, and are disclosed, for example, in U.S. Pat. No. 7,227,112 and U.S. Pat. No. 7,649,682.
As disclosed in U.S. Pat. No. 7,227,112, in scanning microscopes, there are several items to be set, such as pinhole diameter, the voltage of a PMT, the output intensity or wavelength of a light source, or scanning speed, and the image quality may vary greatly depending on these items to be set. For example, in fluorescence laser scanning microscopes (hereinafter referred to as a fluorescence LSM), if a pinhole diameter is made to be sufficiently smaller than an Airy disk diameter, it is known that a resolution exceeding the cut-off frequency of an optical system (hereinafter, referred to as superresolution) is obtained. Such techniques are disclosed, for example, in T. Wilson and C. Sheppard, “Theory and Practice of Scanning Optical Microscopy”, Academic Press, 1984, Chapter 6, Section 6.
A main object of conventional fluorescence LSMs is not to obtain a super-resolution component, but to achieve a sectioning effect. If the pinhole diameter is downsized with reference to the Airy disk diameter in order to obtain a super-resolution component, the amount of fluorescent light detected by a detector may decrease.
For this reason, in conventional fluorescence LSMs, the detection efficiency is prioritized, and the pinhole aperture diameter is generally set to a diameter on the order of the Airy disk diameter.
Fluorescence LSMs have been described in the above, but microscopes in which a super-resolution component is detected are not limited to the fluorescence LSMs. In scanning microscopes, an illumination light is condensed to one spot on a sample, and the spot to which the illumination light is condensed is moved by a scanning unit. Accordingly, the illumination light is modulated spatially or temporally. Hence, a super-resolution component may be detected in scanning microscopes as a whole.